Write Port Control Function (4304) - GE PACSystems RX7i Reference Manual

6.2.10 Write Port Control Function (4304)

This function controls output signals on the specified port:
Example Command Block for the Write Port Control Function
VALUE
(decimal)
Address 0002
Address +1 0000
Address +2 0008
Address +3 0000
Address +4 0000
Address +5 0000
Address +6 4304
Address +7 xxxx
Port Control Word
15 14 13 12
RTS DTR -- --
Port Control Word Meanings:
Commanded state of Request to Send signal
15 RTS 1 = Activates RTS
0 = Deactivates RTS
Commanded state of Data Terminal Ready signal
14 DTR 1 = Activates DTR
0 = Deactivates DTR
13-0 n/a Unused (should be zero)
Operating Notes
For reference, see the tables under Serial Port Pin Assignments in Chapter 5.
Support for the DTR output signal is provided for COM1 only, on all RX7i and RX3i models (except CPE302,
CPE305, CPE330 and CPE400), in Rel 7.16 and later releases.
For CPU COM2 (RS-485), the RTS signal is also controlled by the transmit driver. Therefore, control of RTS
is dependent on the current state of the transmit driver. If the transmit driver is not enabled, asserting
RTS with the Write Port Control COMMREQ will not cause RTS to be asserted on the serial line. The state
of the transmit driver is controlled by the protocol and is dependent on the current Duplex Mode of the
port. For 2-wire and 4-wire Duplex Mode, the transmit driver is only enabled during transmitting.
Therefore, RTS on the serial line will only be seen active on COM2 (configured for 2-wire or 4-wire Duplex
Mode) when data is being transmitted. For point-to-point Duplex Mode, the transmit driver is always
enabled. Therefore, in point-to-point Duplex Mode, RTS on the serial line will always reflect what is
chosen with the Write Port Control COMMREQ.
GFK-2222AD
VALUE MEANING
(hexadecimal)
0002 Data block length
0000 NOWAIT mode
0008 Status word memory type (%R)
0000 Status word address minus 1 (%R0001)
0000 Not used
0000 Not used
10D0 Write port control command
xxxx Port control word
11 10 9 8
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April 2018
Chapter 6. Serial I/O, SNP & RTU Protocols
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